The present invention relates to improvements made to solenoid valves.
It is more particularly applicable to solenoid valves comprising an electromagnet subassembly associated with a pneumatic switching subassembly with valve plug, which is mechanically associated with the said electromagnet subassembly, the pneumatic switching subassembly being composed of a body enclosing the valve plug trapped between two sealing seats facing each other, the said valve plug movement being forced firstly by a spring located in the mobile core of the electromagnet subassembly through a pusher, and secondly by a means that forces the valve plug onto the upper seating of the pneumatic switching subassembly when the electromagnet is energized.
One of the technical problems that arises during the design of this type of solenoid valve is assembly of the electromagnet subassembly on the pneumatic switching subassembly. In particular, this type of assembly must satisfy the following requirements:
ease of implementation and automation of the assembly;
low cost price;
cannot be disassembled;
possibility of using the assembly on machined parts.
Some of these requirements are contradictory, and particularly the possibility of using the assembly on machined parts, a quality that usually causes cost increases.
The objective of the invention is to provide a solenoid valve that solves all these technical problems and also provides other advantages that will be described below.
The solenoid valve according to this invention is characterised in that its electromagnet subassembly comprises four cylindrical pins at its assembly plane on the pneumatic switching subassembly, each cylindrical pin being provided with a transverse cavity formed on the generating line and terminating with the frustum of a sphere, and in that the pneumatic switching subassembly comprises four cylindrical cavities at its assembly plane with the electromagnet subassembly designed to hold the pins of the electromagnet subassembly, transverse cavities being formed on the body of the pneumatic switching subassembly, these cavities terminating on the corresponding generating line of the cavities into which the pins will be fitted, and the said cavities terminating in the frustum of a sphere such that, after the two subassemblies are assembled together, the transverse cavities of the pins of the electromagnet subassembly are facing the transverse cavities of the said pneumatic switching subassembly, delimiting housings into which a ball will fit.
According to this invention, the diameter of each transverse cavity of the pneumatic switching subassembly is less than the diameter of the balls.
According to another characteristic of the solenoid valve according to the invention, the means that forces the valve plug into contact with the upper seating of the pneumatic switching subassembly is made in the form of an xe2x80x9celastic returnxe2x80x9d function integrated into the pusherxe2x80x94valve plug.
According to another characteristic of this invention, the solenoid valve comprises a manual control that is composed of a cylindrical-shaped part that firstly moves the valve plug from the lower seating to the upper seating, and secondly makes the pneumatic switching subassembly leak tight by a leak tightness function integrated into this manual control.
According to the invention, the said manual control may be provided with a return means, returning it to the initial position when it is no longer activated, this return means being made in the form of a steel strip spring that is built in at one of its ends to the body of the pneumatic switching subassembly and which at its other end is housed in the retaining groove of the manual control. The end of this strip spring is built into the body of the pneumatic switching subassembly, and is preferably provided with retaining pins.
Other advantages and specificities of this invention will become clear from the following description with reference to the appended drawings, which illustrate example embodiments without being limitative in any way, wherein: